1. Field of the Invention
The present invention relates generally to measurement systems and more particularly to a measurement system having a large dynamic range.
2. Description of the Relevant Art
One of the objectives in the design of electronic equipment is to provide a large dynamic range. The dynamic range of electronic equipment may be defined in terms of the largest and smallest level of the input signal that can be processed by the equipment. For the purpose of this disclosure the definition of the dynamic range is the ratio of the difference between the magnitude of the largest signal minus the magnitude of the smallest signal divided by the magnitude of the smallest signal.
In the design of infrared radiometers, a large dynamic range means that one instrument can be used to measure a large range in target temperatures. A large dynamic range is useful in reducing the cost of producing an instrument as well as the cost to customers whose processes require a large range. In infrared thermometry the dynamic range required of an instrument can be very large because the electrical signal produced by an infrared detector increases exponentially as the temperature of the target is increased. It may require several models to cover a given range of target temperatures.
At present there are several ways to increase the dynamic range of electronic equipment. These include the use of a logarithmic amplifier, integrating amplifier, or changing in real time the gain of an amplifier.
However, each of the above-described ways have disadvantages of having a slow response time or requiring a multitude of electronic components for realization.